JP2024008897A - Coating module with flexible film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating module with a flexible film to cope with the emergence of ribs, hence improving the homogeneity and quality of a coated layer.

SOLUTION: The invention relates to a coating module (1) to coat a substrate (4) with a coating composition (6), comprising: a coating device (2) to apply a layer of the coating composition on the outer surface of the substrate (4), and a flexible film (5) comprising a distal portion (54) designed to be in contact with the coated substrate (4).

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

FIELD OF THE INVENTION The present invention relates to coating modules for coating substrates and related methods with improved coating quality. The invention further relates to a thermal transfer printing device comprising such a coating module.

BACKGROUND OF THE INVENTION Many coating techniques using free surface coating flow are well known to those skilled in the art and can be applied using rollers, sprays, slot dies, screen printing, extrusions, knives, blades, bars, etc. A substrate is coated with a coating composition.

However, single layer/multilayer methods (i.e. dip coating, rod coating, knife coating, blade coating, air knife coating, gravure coating, forward/reverse roll coating, slot/extrusion coating, slide coating, curtain coating, etc.) , coating compositions applied to substrates are likely to undergo flow instabilities that affect the uniformity of the coating layer, and regardless of the coating technique or the nature of the coating composition, ribs on the coating surface A periodic, undulating coating thickness variation called a ridge pattern is commonly observed. Therefore, it is always a challenge to limit the appearance of ribs and associated defects.

Fluid instabilities are complex in nature, and small fluctuations can propagate to large defects. The origin of the ribs can be diverse as they can be the result of small disturbances occurring during the coating process within the coating composition. Its occurrence depends on several factors, including characteristics of the coating composition such as surface tension, viscosity, coating process parameters such as coating speed, pressure, viscoelastic forces, or locally applied shear rate, and the material of the coating equipment. May depend on factors.

Typically occurs when coating thin layers of a few grams/m2 (e.g. less than 30 g/ ^m2 on a weight basis) or when reaching a final coating layer with a thickness of less than 200 μm at high coating speeds. A limitation is that this may accentuate the prominent sides of the ribs. The ribbing phenomenon can also be accentuated or released during downstream steps of curing, drying, or cooling, whereby processing conditions such as temperature and relative humidity may also affect the final aspects of the coated article. may have an impact.

In general, ribbing refers to a non-uniform coating that results in a wavy thickness profile across the width and is more or less uniform in the coating direction. Ribbing is a flow instability that causes the coating thickness to vary sinusoidally across its width, which can be harmful or even lead to unacceptable permanent defects. Stripes or ribs appear on the surface along the machine direction (also called transport direction or coating direction). This defect is sometimes referred to as corduroy, rake lines, or phonographing. In practice, rib relaxation involves changing coating speed, coating viscosity, wet coating thickness, or adding surfactants to the coating composition. These restrictions conflict with economic drivers.

The present invention aims to provide a new coating module to deal with the appearance of ribs, thereby improving the homogeneity and quality of the coating layer.

SUMMARY The present invention provides a coating module for coating a substrate with a coating composition comprising a coating device for applying a layer of the coating composition to the outer surface of the substrate, and a coating module designed for contacting the coated substrate. The present invention relates to a flexible film having a distal portion (terminal portion).

The present invention is a coating module for coating a substrate with a coating composition, comprising: a coating device for applying a layer of the coating composition to a first surface of the substrate; and a coating device mechanically connected to a holding element. The present invention relates to a coating module comprising a flexible film (5) comprising at least one proximal end thereof and a free distal portion configured to contact a layer of coating composition on a first surface of a substrate.

One advantage is that the free distal portion of the flexible film smoothes the coating surface of the substrate after coating application. It has also been observed that the present invention improves the overall quality of the coating layer by mitigating and reducing other defects caused by streaks.

According to one embodiment, the coating module comprises a conveyor system for supporting and transporting the substrate by its inner surface or a second surface of the substrate opposite its outer surface.

According to one embodiment, the conveyor system includes support rollers.

According to one embodiment, the conveyor system includes a temperature regulator configured to heat or cool a portion of the substrate.

According to one embodiment, the flexible film further comprises apertures, grooves or fibers.

According to one embodiment, the coating module further comprises means for applying pressure to the distal portion of the flexible film.

According to one embodiment, the coating module comprises a holding element, to which the flexible film is fixed, the holding element being mechanically connected to the frame by one or two side ends. One advantage is that the distal free portion maintains the position of the proximal end or end of the flexible film while contacting the coated substrate.

According to one embodiment, the holding element is connected to the frame in at least one angle or degree of freedom. One advantage is to adjust the position of the flexible film. Another advantage is the elimination of streaks between the flexible film and the coated substrate.

According to one embodiment, the retaining element is removable from the frame.

According to one embodiment, the coating module comprises a source of electromagnetic radiation arranged to irradiate the distal portion of the flexible film, the flexible film being transparent to such radiation. One advantage is that it allows the transmission of electromagnetic waves at any desired wavelength or orientation to reach the reactive molecules and orient or polarize the components of the coating composition.

The invention furthermore relates to a coating system comprising a coating module and a substrate according to the invention. The coating device is arranged to coat the surface of the substrate. The flexible film is placed in planar contact with the coated substrate. According to one embodiment, the flexible film is placed such that its distal portion is in planar contact with the coated substrate.

The invention further relates to a thermal transfer printing device. A thermal transfer printing device is equipped with a coating system according to the invention, where the substrate is an endless ribbon. A thermal transfer printing apparatus includes a conveyor system comprising a set of rollers for transporting a substrate along a path, a printing roller for transporting a printing support in contact with an outer surface of at least a portion of the substrate, and a coating. a printing head arranged to thermally transfer a portion of the ink from the outer surface of the substrate to a printing support in contact with the substrate.

The invention furthermore relates to a system for producing an endless ribbon comprising a coating system according to the invention, wherein the substrate comprises a coating drum. One advantage is to form an endless ribbon or band of uniform thickness on the coating drum, for example using a dip coating method. Advantageously, the system also comprises a cylinder and means, such as a motor or rotor/stator pair, for rotating the coating drum about the longitudinal axis of the cylinder.

The invention further relates to a method of coating a substrate.

In one embodiment, the method comprises coating the outer surface of the substrate with a coating composition. The method further includes suspending the flexible film on the holding element such that the free portion of the flexible film lies on the coated outer surface of the substrate before its setting (setting), drying, or complete curing. It comprises transporting the substrate by its inner surface along a predetermined path.

In one embodiment, the step of coating comprises coating the outer surface of the substrate in parallel with at least two bands separated from each other, and the coating module comprises at least two flexible films, each flexible film are placed overlying one band of coating.

In another alternative embodiment, the method includes coating an outer surface of a substrate with a coating composition using a coating device; It comprises transporting the coating device and the flexible film along a predetermined path so as to lie down before drying or before complete curing.

FIG. 1 is a schematic cross-sectional view of a coating module according to a first embodiment of the invention using a slot die coating device. FIG. 2 is a schematic cross-sectional view of a coating module according to a second embodiment of the invention, in which the coating device comprises an ink roller. FIG. 3 is a schematic cross-sectional view of a flexible film of a coating system according to an embodiment of the invention. FIG. 4 is a perspective view of a flexible film of a coating system according to another embodiment of the present invention, wherein the flexible film includes an opening and a coating module includes a flexible film in contact with a coating layer of a coating composition. means for maintaining the distal portion of the FIG. 5 is a schematic cross-sectional view of a flexible film of a coating system according to another embodiment of the invention, where the two longitudinal ends of the flexible film are mechanically connected to a retaining element. FIG. 6a is an illustration of the coating layer showing the ribbing phenomenon captured by a microscope. FIG. 6b is a microscopic view of a coating layer coated with a coating module according to an embodiment of the invention, where the flexible film is 12 μm thick and made of polyester. FIG. 6c is a microscopic view of the coating layer coated with the coating module without flexible film, the coating device comprising an ink roller with surface defects. FIG. 6d is a photometric view of a coating layer coated with a coating module according to FIG. 6c, further comprising a flexible film according to an embodiment of the invention. FIG. 7 is a schematic cross-sectional view of a flexible film and a holding element according to an embodiment of the invention, where the coating module comprises a winding element for storing at least one portion of the flexible film. FIG. 8 is a schematic diagram of a thermal transfer printing apparatus according to an embodiment of the invention. FIG. 9 is a schematic diagram of a coating module according to one embodiment of the invention, where the substrate to be coated comprises a coating drum. FIG. 10 is a schematic diagram of a coating module according to an embodiment of the invention, where the substrate to be coated comprises a coating drum and the coating device comprises a knife coating device. FIG. 11 is a schematic diagram of a coating module according to an embodiment of the invention, where the coating device and flexible film are portable. FIG. 12A is a schematic diagram of a flexible film and a cleaning means for cleaning the flexible film. FIG. 12B is a schematic illustration of a flexible film attached to a retaining element, according to one embodiment, where the flexible film is an endless film and the coating module further comprises means for cleaning a preliminary portion of the flexible film.

Detailed Description In this application, the term "inner surface" is to be understood as the surface of the substrate that is optionally in contact with the conveyor system. Conversely, the term "external surface" is to be understood as the surface of the substrate that receives the coating composition.

As used herein, "substrate," "coating substrate," "coating layer," or "coating layer" refers to a coating composition that is brought into contact with the flexible film. used interchangeably to refer to any surface that receives Such surfaces are designed to produce any kind of coatings or laminates like precoats, skin coats, top coats, back coats, coverings, varnishes, finishes, adhesives for film lamination...etc. A free flow coating composition is provided.

FIG. 1 shows a first example of a coating module 1 according to an embodiment of the invention.

The coating module 1 comprises a coating device 2 for applying a coating composition 6 to the outer surface of a substrate 4 while being transported along a predetermined path by a conveyor system 3 . The coating module 1 further includes a flexible film 5.

The coating module 1 can contain all kinds of coating devices, the flexible film can be coated with flexography, free flow and curtain coating, dip coating, brushing, roll coating (forward roll coating, reverse roll coating...etc.) It is made to comply with all coating techniques available to the skilled person for direct or transfer (indirect) coating, such as, spraying, painting, brushing/wiping, extrusion coating, etc.

The use of flexible films within this coating module could be embedded in any continuous coating process. The present invention is particularly adapted to free flow coatings where the final coating surface must be uniform and smooth.

The coating device is used to dispense the coating composition onto the top surface of the substrate. The coating composition flows to cover the entire or partial area. Thus, flexible films can be designed to completely or partially improve the uniformity of the coating layer applied onto the substrate, for example for strip coating or interrupted coating.

The coating process can consist of a single coating step or multiple coating steps, whereby a series of coating compositions are applied over previous coating layers, such as precoats, whether or not tack-free. It can be applied to

The coating module can also combine several different coating techniques in multi-method coating. The coating could be operated horizontally, vertically, or diagonally at an angle. With double-sided coatings, the inner and outer surfaces may switch during the process. The flexible film is installed to ensure contact with the coating composition while it is still free flowing, ie liquid, viscous or molten, regardless of its viscosity. It is therefore advantageous to be placed between the coating device and the cooling, curing or drying equipment.

Flexible Film During coating, the flexible film is intended to contact the coated substrate. A coating layer is applied to the outer surface of the substrate. The flexible film operates when leveling of the coating remains possible, ie, before its surface is tack-free and before the coating composition is cured, dried, or cooled. Flexible films can accommodate all kinds of coating product imperfections and defects, avoiding ripples, wrinkles, wobbles, and/or abandonment, etc.

At least one end of the flexible film is attached to a holding element for holding it on the substrate. The bending ability of the film allows the distal portion (terminal portion) to cover a portion of the newly applied coating layer on the substrate, while the coating composition can be homogenized or otherwise smoothed. can exhibit appropriate thermomechanical behavior. The coating flattening, leveling, or uniformizing operation is performed in a process window positioned to correspond to the ribs and eliminate thickness irregularities.

In one embodiment, due to the movement of the substrate according to the coating direction and the flexibility of the flexible film, the distal portion of the flexible film is dragged by the substrate. Thus, the coating layer slides under or along the distal portion of the flexible film.

The flexible film is arranged and designed such that the surface of the distal portion of the flexible film is in contact, preferably in planar contact, with the coating layer of the substrate.

By "planar contact" it is to be understood that the distal portion of the flexible film overlies, overlaps, or is juxtaposed with the top coating layer of the substrate. The face of the distal portion 54 of the flexible film represents the surface that contacts the coating layer of the substrate.

The length of the flexible film is designed to be long enough to ensure planar contact between the distal portion and the coating layer. The length of the distal portion of the flexible film can be greater than 0.5 mm, preferably 1 cm or more depending on the coating direction.

In one embodiment, the coating module is capable of coating at least two portions of the width of the substrate simultaneously, forming at least two bands or stripes of coating. According to one example, the coating module comprises a shim. The shim comprises at least two openings and is arranged to guide the coating composition through the openings to form at least two distinct bands or stripes of coating on the surface of the substrate. .

In one embodiment, the coating module comprises at least two flexible films. Preferably, the at least two flexible films are arranged in the same plane fixed to the holding element, each flexible film being arranged so as to overlap part of the width of the substrate. Preferably, each flexible film is disposed over a band of one coating, an outer coating layer or a substrate.

Single End Fixation In the first embodiment shown in FIG. 3, the proximal end 52 of the flexible film 5 is mechanically connected to a retaining element 53. Preferably, the holding element 53 is mechanically connected to the frame of the coating module. Preferably, the proximal end of the flexible film is mechanically connected to the retaining element 53 with zero degrees of freedom.

In other words, the flexible film is fixed and suspended on the holding element 53 by its proximal end above the coated substrate 4 transported by the conveyor system. The length of the flexible film 4 is greater than the distance between the retaining element 53 and the coated substrate 4, so that the distal part 54 of the flexible film overlaps a part of the upper coating layer 6 and bends. Overlying the coated substrate 4.

Fixing both ends In the second embodiment shown in FIG. 5, both ends of the flexible films 521, 522 are mechanically connected to the holding element 53. In this embodiment, the flexible film 5 forms a closed loop. The distal portion 54 remote from the retaining element is arranged in contact with the coating layer 6 . The first advantage is to prevent defects due to resulting miscuts or sharp edges 58 in the flexible film. The second advantage is to reduce the risk of losing contact between the flexible film and the coated substrate, applying slight pressure as the film flexes onto the substrate. A third advantage is that it reduces the risk of misalignment between the distal portion 54 of the flexible film 5 and the substrate.

In both the first and second embodiments, the flexible film could be placed in contact with the substrate as close as possible from the coating device.

Additional Embodiments In addition to the first or second embodiment described above, other embodiments will be described.

In one embodiment shown in FIG. 7, the coating module comprises at least one unit 61 or 62 for winding up a portion of the flexible film. In one embodiment, at least one take-up unit is designed to store a fixed amount of film.

In a further embodiment, the coating module comprises a first unit 62 and a second unit 61. Preferably, the first unit and the second unit are mechanically connected to the holding element 5. The flexible film is held between the first unit 61 and the second unit 62 such that the length of the flexible film from the first unit to the second unit is longer than the distance between the first unit and the second unit. to form a storage unit for the flexible film. One advantage is to condition the distal portion 54 of the flexible film in contact with the newly coated layer 6.

In one embodiment, the first unit and/or the second unit comprises at least one winder. The user can unwind the flexible film from the first unit 62 and cut the old part of the flexible film to renew the distal part of the flexible film intended for contacting the coating layer. In one embodiment, the first unit and/or the second unit comprises at least one motor for controlling the winder and its rotational speed.

When the flexible film is rolled up from the first unit and onto the second unit, its distal portion in contact with the coating layer can be renewed. A reserve of flexible film stored in the first unit is rolled out and spread over the coating layer. The unwound portion of the flexible film becomes the new distal portion. One advantage is the continuous replacement of the distal portion of the flexible film.

In one embodiment, the coating module 1 further controls a degradation sensor designed to measure the degradation of the flexible film. The degradation sensor can include at least one optical sensor. In one embodiment, the coating module includes means (for the first and/or second unit) for automatically replacing the distal portion of the flexible film when the degradation measured by the degradation sensor reaches a predetermined threshold. (e.g., a controller that controls the motor of the motor). One advantage is automatic exchange of the distal portion of the flexible film.

Preferably, the holding element 53 is mechanically connected to the frame of the coating module 1. Advantageously, the holding element 53 has fixing means for fixing one or both ends of the flexible film 5.

In one embodiment, the coating module 1 comprises at least two flexible films 5, each flexible film 5 being fixed to a holding element 53. Multiple coating steps allowed multiple arrays of flexible films as described above to be connected to the same frame or operated independently. Each holding element 53 can be mechanically connected to the frame of the coating module 1 with at least one rotational or translational degree of freedom. This degree of freedom, together with the ease of replacing the flexible film 5, makes alignment of the flexible film advantageous.

In one embodiment, at least one end of the flexible film is attached to the holding element with double-sided tape. The flexible film is glued, clamped, nailed, screwed and riveted to the holding element 53.

In another embodiment, the coating module comprises means for easily changing or replacing the flexible film 5. In one example, the first unit 61 and/or the second unit 62 are removably connected to the holding element 53 or the frame. In a second example, the flexible film is connected to the frame or retaining element by removable fastening means, such as screws, tongs, adhesives or magnetic fastening means. In one embodiment, the holding element may be combined with a drying unit as described below.

In another alternative embodiment, the flexible film and the holding element are mounted according to the invention on a portable support device intended to be placed on the ground and intended to suspend the flexible film above the substrate. Good too.

In another embodiment, the coating module further comprises means for providing lateral movement to the flexible film. The means can induce vibration means for providing vibrations to the flexible film. Vibration of the flexible film may improve the reduction of rib effects on the coating layer 6. Another advantage of vibration is that it improves the removal of defects caused by the presence of particles, dust, air bubbles, prematurely dried coatings, small pieces, streaks caused by lumps, or caused by nicks in the coating device. That's true. Therefore, the quality of the coating layer could be improved by mitigation of air pockets in the coating composition remaining after filtration or other operations performed before the actual coating.

In one embodiment, the vibration means may comprise a motor controlling the holding element or the piezoelectric element. In one embodiment, the coating module includes a controller. A controller controls the vibration means. In one embodiment, the controller automatically activates the vibration means to provide vibrations to the flexible film periodically and/or when a streak is detected between the flexible film and the substrate. It is configured as follows.

In one embodiment, the coating module comprises means for providing translation or rotation of the retaining element 54. The axis of rotation is desirably parallel to the length direction of the flexible film.

In one embodiment, the holding element is mechanically fixed with a frame having at least one or two degrees of freedom in translation and/or rotation. One advantage is that the retaining element can be moved to adjust the position of the flexible film to the orientation and position of the substrate.

In one example, the retaining element is free to translate in a first direction perpendicular or perceptually perpendicular to the surface of the substrate. One advantage is to adjust the length of the distal portion in contact with the substrate.

In one alternative or cumulative example, the holding element is free to translate in a second direction parallel or perceptually parallel to the transport direction of the substrate. One advantage is to reduce or eliminate streaks.

In one embodiment, the movement of the hold according to the second direction is controlled by a controller. In one embodiment, the controller is configured to periodically automatically provide movement (such as a back and forth movement) of the retention element according to the second direction to remove streaks.

In one embodiment, the coating module includes a sensor, such as an optical sensor, to detect streaks between the flexible film and the substrate. The sensor is connected to a controller, and the controller is configured to initiate movement of the holding element as a function of the sensor measurement.

Preferably, the flexible film is suspended from the holding element such that the direction of the film from its proximal end to its distal portion corresponds sensibly to the direction of transport of the substrate.

In one embodiment, the film 5 is arranged such that the film 5 and the substrate 4 are aligned edge-to-edge, and optionally the width of the substrate 4 is equal or perceptually equal to the width of the flexible film. The flexible film 5 is necessarily curved over the coating surface and aligns or orientations depending on the direction of transport or coating induced by the conveyor system. Another advantage of the design is the precise control over the spreading and leveling of the coating on the outer surface of the substrate and its width edge.

Desirably, the width of the flexible film is between 100% and 50% of the width of the substrate.

In another embodiment, the coating composition is applied to the central portion of the substrate. In such embodiments, the width of the flexible film can be adjusted to control the spread of the coating composition beyond the initial width, thereby controlling subsequent width and thickness.

The chemical composition of the flexible film can be selected, but is not limited to any of the following materials or combinations thereof. Flexible films are based on thermoplastic, thermosetting or elastomeric polymers, such as polyesters, polyamides, polycarbonates, polyolefins, polysulfones, polyurethanes, vinyl or cellulose derivatives, fluorinated or chlorinated derivatives, polyallyletherketones, polybenzimidazoles. , polyethylene glycol, polyimide, polyurethane, acrylic styrene, acrylic copolymer, and mixtures thereof. The flexible film can advantageously be made of materials based on polyethylene terephthalate (PET) or its derivatives, polyimide, PTFE ("polytetrafluoroethylene") or PEEK ("polyetheretherketone").

In another embodiment, the flexible film is a foil or sheet of metal, such as aluminum. In another embodiment, the flexible film is comprised of a combination of polymeric and metallic layers. In another embodiment, the flexible film includes at least one filler selected from powders, fibers, whiskers, particles, nanosheets, etc. The filler can be selected from carbon, carbon black, graphite, graphene, carbon nanotubes, activated carbon nanotubes, activated carbon fibers, inactive carbon nanofibers, metal flakes, metal powders, metal powders, metal fibers.

The material and thickness of the flexible film allows the flexible film to contact the substrate along a distal portion, which is supported by the moving substrate.

In one embodiment, the film is tailored to be transparent or opaque to electromagnetic fields. The flexible film may be transparent to ultraviolet (UV) radiation to cause a photochemical reaction when a UV curable composition is used. This embodiment is particularly advantageous for thick coatings. In fact, the solidification (solidification) reaction can advantageously be triggered at depth (deep penetrating hardening). Therefore, reactions can be initiated within the bulk coating while the surface remains liquid, which allows the flexible film to improve the quality of the top coating layer. Conversely, the film can block such electromagnetic waves to prevent premature curing near the coating device, for example in a luminescent environment.

In other embodiments, the flexible film may be transparent, transparent, or porous to other types of radiation, such as electron beams, lasers, plasmas, corona, etc. The flexible film is also transparent to and capable of transmitting electromagnetic waves such as linear, circular, or elliptical waves used to polarize the coating composition in situ.

In one embodiment, the flexible film has a Young's modulus of less than 10 GPa, preferably 5 GPa or less. The thickness of the flexible film is greater than 1 μm. The thickness of the flexible film is preferably in the range of 3 μm to 50 μm, more preferably in the range of 3 μm to 15 μm. This thickness of the flexible film is advantageously suited for coating thin layers (eg, layers thinner than 100 μm).

In another embodiment, the thickness of the flexible film is greater than 50 μm, or desirably greater than 100 μm. This thickness of the flexible film has the advantage that it can be handled more easily manually and helps maintain contact between the flexible film and the coated substrate.

If desired, the flexible film basis weight can be lower than the wet coating basis weight. One advantage is that the uniformity of the coating layer thickness can be better controlled. In one embodiment, the basis weight of the flexible film is less than 30 g/m ² , preferably less than 20 g/m ² . The combination of mechanical properties and chemical/physical characteristics of the flexible film is such that it ensures the formation of a free floating curvature of the flexible film between the retaining element and the distal part in planar contact with the coating. can be selected or adjusted.

In one embodiment, at least one surface of the flexible film 5 is textured.

In one embodiment, the flexible film comprises a texture over limited areas. Preferably, the grooves are distributed over the area closest to the retention element, allowing the last part of the distal part to come into contact with the substrate. One advantage is the progressive effect of smoothing the flexible film onto the coating layer.

In one embodiment, the flexible film is comprised of patterns or randomly decorated grooves.

Preferably, the grooves are created by laser ablation. Preferably, the grooves include a plurality of grooves extending in a direction that is not parallel to the transport direction of the substrate.

One advantage is that this diagonal groove allows a perturbation of the coating layer 6 on the substrate 4 to be created. The grooves therefore advantageously reduce ribs when leveling of complex coating compositions is otherwise difficult to achieve.

In one embodiment, this groove extends along the surface of the flexible film 5 along a direction that represents an angle of 10° to 30° with the transport direction of the substrate. Surprisingly, the inventors have discovered that this particular orientation of the grooves further improves the quality of the coating. In fact, such an arrangement induces further shear in the upper coating layer, leading to a significant reduction in the rib effect.

In one embodiment, the groove depth ranges from 1 to 10 μm. In one embodiment, the width of the groove ranges from 0.5 to 10 μm.

In one embodiment shown in FIG. 4, the flexible film 5 comprises at least one aperture 56 or a plurality of apertures 56. Preferably, the opening is located on the flexible film 5 in the area between the distal portions 54. More preferably, the opening 56 is located close to the distal portion 54 of the flexible film 5 in contact with the coating layer 6.

Opening 56 is advantageous in maintaining contact between distal portion 54 and the coating layer on the substrate.

In fact, if the speed of the substrate 4 is increased, the air resistance against the flexible film 5 may cause the flexible film 5 to peel off from the coating layer 6, thereby reducing the quality of the coating. Additionally, the openings may provide holes in the flexible film for radiation to pass through and reach the coating composition, as described above.

It is desirable that the opening 56 be a through hole along two sides of the flexible film. The surface of this opening is preferably in the range of 1 μm ² to 10 μm ² .

In one embodiment, the flexible film 5 presents two sides with different surface energies. Optionally, the surface of the flexible film in contact with the coating layer 6 is more lipophilic or hydrophilic than the outer surface of the substrate 4 in contact with the coating layer, and vice versa. Preferably, the flexible film 5 is made of lipophilic material and the outer surface of the substrate is made of lipophilic material. Adjusting the surface tension of the flexible film depending on the coating composition enhances contact with the distal portion. In one embodiment, the surface energy of the film is precisely 50 mN/m on both sides. Effective contact between the distal portion of the film and the coating layer is therefore enhanced by capillary forces and shear within the fluid creates a homogenizing effect.

In one embodiment, the flexible film is designed to adjust the spread and control the distribution of the coating composition across its width.

In one embodiment, the flexible film comprises a fibrous structure. In one embodiment, the fibrous structure is placed on a fabric. The fabric can be woven, non-woven, knitted, braided, or any other type of open or closed structure.

In one embodiment shown in Figure 4, the coating module 1 further comprises means for applying pressure to the distal portion of the flexible film to maintain contact with the coating layer.

In one embodiment, these means comprise a plate 55 intended to be in planar contact with the outer surface or with the flexible film 5 and furthermore with a force directed towards the substrate 4 from above the distal part 54 of the flexible film 5. It is possible to include an arm 57 that causes the plate 55 to generate This plate 55 therefore advantageously presses the flexible film 5 in order to maintain contact between the flexible film 5 and the coating layer 6. The arm 57 can be moved translationally and/or rotationally relative to the frame of the coating module 1 in order to generate a force by the plate 55 towards the substrate 4 .

In another embodiment, the means for applying pressure to the distal portion of the flexible film comprises a fan arranged to generate an air flow towards the distal portion of the flexible film. In this case the pressure is applied by air. In another embodiment, the means for applying pressure comprises any type of pressing element, such as a roller.

In one embodiment, plate 55 includes means for securing to the flexible film. The plate 55 may be provided with means for bonding, connecting, pasting or adhering to the flexible film.

For example, the plate 55 can be equipped with an adhesive or a suction system. These means advantageously enable plate 55 to remove the flexible film when arm 57 removes plate 55.

One advantage is better control of the width coating distribution while the coating composition slides along the flexible film. Indeed, given that flexible films exhibit wetting properties associated with coating compositions, it is possible to coat a narrower portion of the substrate and spread the coating layer across its width. This setup could be used advantageously in combination with applied pressure to maintain or press the flexible film to the coating layer. Coating widths have been increased to reduce the amount of coating poured or applied onto the substrate, allowing the perfect reduction in thickness and opening new process windows to reduce coating stripes and intermittent coatings. management becomes possible.

Plate 55 conducts electricity and can also be connected to system ground. One advantage is improved electrostatic dispersion and reduced risk of sparks and fire. In one embodiment, plate 55 is made of metal or conductive plastic.

In another improved embodiment, the flexible film is made of an electrically conductive material and the coating module comprises means for passing an electric current through the flexible film.

An advantage is that the passage of electric current orients the polar molecules of the coating composition or conductive filler. The coating module preferably comprises a generator connected to the flexible film for transmitting an electromagnetic field through the flexible film.

In one embodiment, the coating module 1 further comprises means for removing the flexible film 5 from the substrate or coating layer. In another embodiment, the flexible film can be optionally removed for replacement, eg, in performance of a maintenance operation.

Conveyor System The coating module may comprise a conveyor system 3. The conveyor system is designed to support and transport the substrate 4 along a predetermined path. Preferably, the conveyor system is designed to drive the substrate from the coating device to the flexible film.

The conveyor system is preferably designed to drive the relative speed of the substrate in a controlled manner during coating.

In one embodiment, the conveyor system 3 is designed to hold and transport the substrate 4 by its inner surface along a predetermined path.

The conveyor system 3 may comprise at least one roller 30. In one embodiment, the conveyor system 3 comprises at least one drive roller. The drive roller is connected to a motor to rotate the drive roller. Rotation of the drive roller advantageously drives the substrate.

The coating module 1 may further comprise a motor for rotating the drive roller of the conveyor system and a speed controller coupled to the motor for generating the rotation of the drive roller. The speed of the substrate along its path is then related to the rotational speed of the drive rollers of the conveyor system and is controlled by a speed controller.

In one embodiment, at least one battery or electrical termination may be implemented in the conveyor system to power the motor.

In another not-illustrated embodiment, the support roller 30 can be replaced by a guide for guiding and supporting the substrate 4 by its inner surface. Preferably, the guide is a curved guide or a partially rounded guide. The guide is static relative to the frame of the coating module. This guide may be a flat surface or a curved surface in order to guide the movement of the base material 4.

Coating Composition A coating composition is a solution, slurry, dispersion, emulsion, paste, ink, slurry, or any liquid, fluid, solvent-based, melt, or viscous composition, or chemical composition of any kind. could be. The coating composition is applied to the outer surface of the substrate and is intended to solidify, dry, harden, or cool after passing under the flexible film. The coating composition can comprise a sol-gel composition or any transitional composition between a fluid and a solid or a polymeric composition.

The coating composition can comprise one or more polymers selected from thermoplastic polymers, thermoset polymers, elastomers, and mixtures thereof.

Examples of thermoplastic polymers include polymers derived from the polymerization of aliphatic or cycloaliphatic vinyl monomers such as polyolefins (including polyethylene or polypropylene), polymers derived from the polymerization of aromatic vinyl monomers such as polystyrene, acrylics, etc. and/or (methacrylic acid) polymers derived from the polymerization of acrylic acid monomers, including, but not limited to, polyamides, polyetherketones, polyimides.

Examples of thermosetting polymers include thermosetting resins (epoxy resins, polyester resins, etc.), optionally mixed with polyurethane or polyether polyols.

Examples of elastomeric polymers include, but are not limited to, natural rubber, synthetic rubber, styrene-butadiene copolymers, ethylene-propylene copolymers, and silicones.

The coating composition can include one or more fillers.

Examples of fillers include, but are not limited to, carbon, graphite, graphene, metals, oxides, and ceramics.

The shape of the filler can be, but is not limited to, particles, flakes, powders, fibers, nanofibers, nanotubes, whiskers, aggregates, sheets of any size range.

The coating composition may be any combination of all of the above.

In one embodiment, the coating composition comprises a solvent, and evaporation of the solvent results in drying or solidification of the coating composition. In such embodiments, the coating module may be equipped with means for promoting evaporation of the solvent, such as a heat source or air blow. Desirably, the heat source or airflow is directed toward the coated outer surface of the substrate after the substrate has passed along the flexible film.

In an alternative embodiment, the coating composition comprises a melt ink. The molten ink is intended to cool and solidify after coating. In one embodiment, the coating module comprises means for promoting solidification of the coating layer, such as a cooler. In one embodiment, the cooler may include a cooling roller 201 as shown in FIG. The cooling roller 201 is arranged to support the inner surface of the base material, and cools the composition coated through the base material. Preferably, the flexible film is placed to slide over the coated substrate between the coating device and the cooler or cooling roller.

In another alternative embodiment, the coating composition comprises a chemical compound that reacts with an electromagnetic field, such as a polarizable molecule or a photoinitiator. In the example of photoinitiators, these compounds are capable of UV curing the coating composition upon UV radiation. In this embodiment, the coating module includes a curing unit that exposes the coating layer to radiation. In one example, the curing unit is arranged to expose the coating layer to ultraviolet light through the flexible film to initiate a photoreaction as described above. In this embodiment, the flexible film is transparent or transparent to such radiation, as previously explained.

In either case, the physical, chemical, or mechanical characteristics of the flexible film are selected by the coating composition.

Substrate The substrate 4 can be any surface for coating. If desired, it can also be a flat surface such as metal, glass, paper, fabric, or plastic. In one embodiment, the substrate is a sheet or foil. In one embodiment, the substrate comprises a ribbon, such as a polyimide ribbon. The ribbon may be a band or an endless ribbon. In one embodiment shown in FIG. 9, the substrate is a coating drum 37, as explained in the description below.

Coating Device The coating device 2 may be any type of coating device capable of coating a layer of fluid onto a substrate. The coating device is designed and arranged to apply a layer of the coating composition onto the outer surface of the substrate, preferably when the wet coating substrate has a weight of less than 30 g/m ² and/or a thickness of The thickness of the layer is less than 100 μm.

Preferably, the coating device is mechanically connected to the frame of the coating module.

Coating devices are intended for applying a layer of coating composition to the external surface of a substrate. The coating device is arranged to apply the coating composition to the substrate within a so-called "coating zone". A "coating zone" is defined by the portion of the substrate that contacts a portion of the coating device or to which the coating composition is applied. This "coating zone" may correspond to the length of the substrate that receives fresh ink from the coating device.

In one embodiment, the coating device is designed to coat both sides of the substrate. Coating compositions can exhibit very low viscosities, close to water, as well as viscosities up to several thousand centipoise. Coating compositions can be cured or cured using conventional techniques such as drying solvent-based or water-based compositions, inducing polymerization or crosslinking reactions, triggering radiation-curable compositions, or cooling molten coating compositions. solidified.

Desirably, the flexible film is positioned such that a distal portion of the flexible film is in contact with the upper coating layer.

As shown in Fig. 6b, the quality of the coating layer obtained using the coating module according to the invention with flexible film is more homogeneous than that obtained without using flexible film as shown in Fig. 6a. . In fact, the surface appearance of the coating layer in Figure 6b has been obtained with a 12 μm thick and 22 mm long flexible film comprising polyester.

In Figures 6a and 6b, white pixels indicate surfaces with low coating thickness and black pixel surfaces indicate surfaces with high coating thickness.

The present invention has been found to advantageously improve coating uniformity on a substrate, which is particularly advantageous for coating ink donor ribbons for thermal transfer printing applications, for example.

Another advantage of the flexible film is that it eliminates defects from the coating layer induced by defects on the outer surface of the ink roller.

The inventors further surprisingly discovered that such flexible films are very efficient in limiting the effects of defects on the outer surface of the ink roller.

An example is given by comparing Figures 6c and 6d. In both cases, the coating layer is applied by a coating device comprising an ink roller 24, as shown in FIG. The same coating section is recorded using a microscope or a backlit telecentric camera system to check the quality of the top coat layer.

In fact, if the ink roller 24 exhibits some defects on the outer surface, subsequent scratches will appear on the coating layer. Such flaws occur in the coating layer due to the abnormal presence of impressions on the ink roll, as shown in Figure 6c. When using the flexible film according to the invention, the inventor observed that the impact of such defects 65 disappeared, as shown in Figure 6d. Ink roll defects cause scratches in the coating layer on the same portion of the coated substrate, which disappear when the flexible film is used. Therefore, not only the ribs in the coating were alleviated, but also the scratches caused by defects on the outer surface of the ink roller were also alleviated.

Therefore, by using a flexible film, it was possible to limit the replacement of damaged ink rollers while maintaining the high quality of the coating layer. Therefore, the present invention has the advantage of limiting ink roller replacement, increasing the usage of coating modules, and improving the overall process throughput and yield.

According to one embodiment, the coating module 1 is provided with additional heating means if the coating composition needs to be softened or melted. The additional heating means increase the temperature of the coating layer 6 above the melting point of the coating composition or below the glass transition temperature of the coating composition until the coating layer 6 reaches the distal portion 54 of the flexible film 5. Guaranteed to be expensive.

This additional heating means advantageously ensures that the coating composition remains sufficiently liquid or viscous to contact and deflect the distal portion 54 of the flexible film. Additional heating means are advantageous to keep the coating composition at a sufficiently low viscosity so that capillary forces can allow interaction between the film and the substrate. Therefore, it is desirable that the flexible film be designed to reach a level of flexibility such that capillary forces can govern the interaction between the flexible film and the substrate.

As shown in Figure 3, the distal portion 54 of the flexible film 5 is in contact with the coating layer 6, which is supported by a support element 30, such as a support roller. The distal portion 54 of the flexible film 5 is in contact with the coating layer 6 and is preferably supported by the conveyor system 3 or support rollers 30. In one embodiment, the support roller 30 comprises heating means, such as an electrical resistance, for heating the substrate 4 in contact with the surface of the support roller 30 .

The support roller 30 is preferably arranged to support the substrate 4 from at least the coating zone to the distal portion 54 of the flexible film 5 and heats the coating layer 6 from at least the coating zone to the distal portion 54 of the flexible film 5. is designed to.

In one embodiment, the coating module 1 comprises means for heating the coating layer 6 by means of radiation.

The means may comprise an infrared source or other thermal radiation source arranged to heat the flexible film 5. In this embodiment, the flexible film 5 is made of a material that converts the radiation emitted by the thermal radiation source into heat. For this purpose, the flexible film 5 may be made from a metal sheet, such as a gold sheet or a titanium sheet.

In another embodiment, the thermal radiation source may be replaced by a radiation source, such as a UV source, capable of initiating polymerization or reticulation at the depth of the coating layer.

In such an embodiment, the flexible film 5 is made of a material that is transparent to the radiation emitted by the radiation source or the thermal radiation source.

Example 1: Slot Die Coating Device Figure 1 shows one embodiment of a coating module according to the invention. The coating device 2 comprises a slot die coating device 21 . Slot die coating device 21 is designed to melt and dispense coating composition 6 onto substrate 4 . The slot die coating device 21 may also include a fluid reservoir for storing a primary source of coating composition and a pump for driving the coating composition through the inlet 23 of the slot die head 21. The slot die further comprises a slot 22 formed for applying the coating composition to the substrate 4, which is designed to measure the amount of coating composition, e.g. wet coating with a reference weight of 10 g/ ^m2. It is applied to a 2 μm foil base material with a thickness of around 1.5 μm.

While the coating composition is being extruded from the slot die, a meniscus is formed between the slot die tip and the substrate that can cause flow instability. The presence of the flexible film 5 prevents ribs caused by such flow instabilities and levels the thin coating layer.

Furthermore, slot die coating is often chosen to produce stripes along the coating direction. The use of several sections of flexible film 5 arranged across the width of the substrate allows for leveling of the coating composition and sharpening of the edges of each coated stripe. Therefore, the risk of overlapping stripes is significantly reduced and the cleanliness of the coating is improved.

The conveyor system 3 is designed to drive the relative speed of the substrate 4 to the slot die coating device 21.

In the embodiment shown in FIG. 1, the conveyor system 3 comprises at least two rollers 30 shown supporting the substrate 4 on either side of the slot die coating device 21. In the embodiment shown in FIG.

Example 2: Ink roller coating device Figure 2 shows another embodiment of a coating module 1 according to the invention. In this embodiment, the coating device 2 comprises an ink roller 24 . The ink roller 24 is attached to rotate by itself, and conveys ink onto a circumferential surface. Coating is performed while the circumferential surface of the ink roller is in contact with the substrate, and the coating composition is transferred to a predetermined thickness.

In one embodiment, the circumferential surface of ink roller 24 is stamped and consists of regularly spaced indentations forming a series of grooves, cavities or patterns. The depth of the depression is comprised between 5 μm and 50 μm. The depressions are advantageous for transporting the coating composition until the ink roller 24 contacts the substrate 4.

The ink roller may be an anilox roller or a flexographic roller.

Example 3: Thermal Transfer Printing Device In another aspect, the invention relates to a thermal transfer printing device 200 with an endless ribbon. Such a thermal transfer printing device 200 will be explained with reference to FIG. 8.

The thermal transfer printing device comprises a coating module 1, which can be any type of coating device. In this example, the coating device is an ink roller designed to force molten ink onto the coating substrate. The substrate is an endless ribbon, such as a polyimide-based ribbon, whose interior is driven by a conveyor system along a path defined by an arrangement of rollers.

The thermal transfer printing device 200 comprises a print head 101 for thermally transferring a portion of the coating layer 6 from the ribbon to a printing support 202 . The endless ribbon 4 is then transported from the print head 101 to the coating device 1 and recoated.

The thermal transfer printing device 200 further includes a plurality of rollers 201 and 204 that hold and transport the endless ribbon 4.

In one embodiment, the thermal transfer printing device further includes a cooling element. The cooling element is designed to actively cool the coating layer 6 on the ribbon between the print head 101 and the coating device 1. Preferably, the flexible film 5 is placed in contact with the substrate 4 between the coating device 1 and the cooling element 201.

As mentioned above, the cooling element may comprise a cooling roller contacting the inner surface of the substrate 4.

The printing device 200 includes a print head 101. In one preferred embodiment, printhead 101 is a thermal transfer printhead.

In the first mode, the print head 101 is in contact with the inner surface of the ribbon 4, allowing thermal transfer of ink located on the outer surface of the ribbon 4. During this printing process, the outer surface of the ribbon 4 is attached to a substrate such as a paper sheet (referred to herein as the "printing support") in order to transfer a portion of the ink for printing the printing support 202. 202 (preferably pressurized contact).

In the second mode, the print head 101 is not in contact with the endless ribbon 4. This mode may be activated when the printing device is switched off or during two consecutive printing sequences. The alternation between the first mode and the second mode can be set by the print mode.

At least one printing roller 203 or printing plate can be used to transport the printing support 202 into contact with the ribbon 4 while thermal transfer is occurring. Thermal transfer print head 101 is designed to transfer hot melt ink from ribbon 4 to printing support 202. The alignment between the print head 101, the ribbon 4 and the print support 202 may be ensured by precisely configured mechanical parts depending on the required printing precision. Several guide and position control components may be implemented to ensure at least a predetermined alignment between print head 101 and ribbon 4.

The printing roller 203 ensures sufficient pressure on the printing support 202 to keep it in contact with the ribbon 4 as the printing process takes place. In this configuration, the ribbon 4 is maintained in a moving sandwich layer between the print support 202 and the print head 101 during the printing process. The movement of the print support 202 is in the same direction as the direction of displacement of the ribbon 4 near the print head 101. Preferably, this movement near the print head is a linear movement.

On its outer surface, the ribbon 4 of the printing device 200 makes it possible to transport ink from the coating module 1 to the print head 101.

The printing process is implemented to form a continuous loop process. During printing, print head 101 contacts the inner surface of ribbon 4, allowing ink on the outer surface of ribbon 4 to be thermally transferred to printing support 202. After printing, the endless ribbon 4 is transported from the print head 101 to the coating device 1 and re-coated. The residual ink is then collected and the coating layer is replenished by the coating device. This configuration allows recovery and rejuvenation of the unprinted, partially emptied ink layer. The ink can advantageously be reused in the next turn of the ribbon 4.

Example 4: Coating a Coating Drum In one embodiment shown in FIG. 9, the substrate is a coating drum 37. The coating drum 37 includes a cylinder such as a rotating cylinder. The conveyor system comprises means for rotating the coating drum 37 about its cylinder longitudinal axis A.

The conveyor system may include a drive shaft 38 that drives the coating drum 37 in rotation. The coating drum 37 is rotationally driven by a motor connected to a drive shaft 38.

The coating device 2 is arranged to coat the outer surface of the coating drum 37 while the coating drum is rotating. The flexible film 5 is placed in contact with the coating layer as described herein.

A coating drum is used to support one or more coating layers designed to use the one or more coating layers to produce a band or endless ribbon. Such substrates advantageously allow for the creation of seamless bands or endless ribbons with surface profile improved coating compositions. This band could be used as a substrate for coating with the aforementioned thermal printer.

Example 5: Knife Coating FIG. 10 shows another embodiment of a coating drum 37 according to one embodiment of the invention.

In this illustrated embodiment, the coating drum is partially immersed within a tank 28 filled with coating composition. A stationary knife coating device 2 is provided to control the thickness of the coating layer within the coating drum.

Rotation of the coating drum through the coating composition continuously supplies the meniscus standing between the substrate and the knife. The movement of the substrate ensures the deposition of layers as it passes the knife. The thickness of the coating layer is related to the gap size between the knife and the substrate and, to some extent, the substrate speed. Knife coating is suitable for depositing uniform layers over large areas and can be performed at high speeds (>10 m/s).

A flexible film is also provided and positioned such that a distal portion of the flexible film contacts the coating surface of coating drum 37.

Example 6: Movable coating module In one embodiment shown in FIG. 11, the coating device 2 and the flexible film 5 are mechanically connected by an arm 29. Arm 28 is connected to movable base 18. The movable base is movable on the ground. In one embodiment, movable base 18 includes one or more wheels for translational movement on the ground.

In this embodiment, the base material 4 is fixed. In one example, the substrate is placed on a fixed support 17.

During coating, the base 18 moves along a trajectory such that both the coating device and the flexible film move along or across the substrate 4. In this embodiment, "transport direction of the substrate" is to be understood as the direction of the substrate with respect to the coating device 2.

Example 7: Cleaning Means In one embodiment shown in FIGS. 12A and 12B, the coating module comprises cleaning means 591 for cleaning the portion 59 of the flexible film 5. In one embodiment, the cleaning means 591 comprises a foam or sponge arranged to contact the surface of the flexible film 5. One advantage is cleaning the surface that was in contact with the coating layer of the substrate. Therefore, the flexible film 5 can be reused and the lifetime of the coating module is advantageously improved.

In another embodiment, the cleaning means 591 comprises a tank filled with a cleaning liquid arranged such that the flexible film passes through the cleaning liquid. Preferably, the composition of the cleaning liquid is designed to remove ink from the flexible film.

As shown in Figure 12A, the cleaning means 591 is arranged between the distal portion 54 and the first unit 61 to wind up the flexible film. When the flexible film 5 is wound into the first unit 61, the cleaning means 591 cleans the flexible film 5. When the flexible film 5 is unwound from the first unit 61 and wound into the second unit 62, the new distal part of the flexible film 5 is cleaned after two passes through the cleaning means. Preferably, the coating module comprises rollers 63 for guiding the endless ribbon between the cleaning means 591 and the first unit 61.

In another embodiment shown in FIG. 12B, the flexible film 5 is an endless flexible film forming a loop. The path of the flexible film forming the loop is predetermined by the position of several support elements 531, 532, and the cleaning means are arranged to clean a portion of the flexible film.

Preferably, the cleaning means 591 are in contact with a part of the endless flexible film between the distal part 54 and the support element 532 supporting the flexible film 5. One advantage is cleaning the flexible film before contacting the support element. It is advantageous to reduce the risk that such support elements become soiled with ink and coating composition residues.

In one embodiment, the cleaning means 591 is embedded or fixed in the retaining element 53.

Preferably, the coating module comprises an additional conveyor system for driving the flexible film along a predetermined path past the cleaning means 591. The conveyor system may include rollers 531 and/or drive rollers 532 for driving the flexible film.

In one embodiment, the coating module comprises a controller for controlling the first and/or second unit or an additional conveyor system for controlling the passage of the flexible film 5 through the cleaning means 591.

Process Performed According to another aspect, the invention refers to a process for coating a substrate. According to this specification, this process is preferably carried out in a coating module and/or a flexible film.

The process comprises a first step of coating the outer surface of the substrate with a coating composition. The coating composition is coated by the coating device while driving the substrate at a relative speed with respect to the coating device and/or the holding element 53.

As previously explained, coating can be performed with any coating device, such as a slot die coating device, a knife coating device, an ink roller, etc.

In a second step, the wet coating layer within the substrate is driven along a predetermined path into contact with the distal portion 54 of the flexible film 5.

Preferably, the coating layer slides along the distal portion of the flexible film by a distance of more than 5 mm, preferably more than 1 cm.

The process can further include downstream steps of drying, cooling, or curing the coating layer after passing under the flexible film. Drying or solidification of the coating composition may occur after the step of sliding along the distal portion of the flexible film. This solidification is accomplished by evaporation of the solvent present in the coating composition or by cooling the coating composition below its glass transition temperature.

In one alternative embodiment, the coating device 2 and the distal portion 54 of the flexible film are driven along a predetermined path into contact with the outer surface of the substrate. In each case, the substrate is moving relative to the coating device and/or the holding element of the flexible film.

Cooling of the coating composition can be accomplished by contacting the substrate with a cooling roller or other cooling device as described above, including a fan.

The process may further include means for switching substrate sides. For coating devices, the inner surface becomes the outer surface and the outer surface becomes the inner surface, so that the substrate is coated on both sides. In this implementation, at least one flexible film can be used to smooth the relative top coating layer.

Claims (15)

A coating module (1) for coating a substrate (4, 37) with a coating composition, comprising:
a coating device (2) for applying a layer of coating composition (6) to a first surface of said substrate (4, 37);
at least one proximal end (52) mechanically connected to a retention element (53) and configured to contact said layer of coating composition (6) on said first surface of said substrate (4); a flexible film (5) comprising a free distal portion (54);
A coating module (1) comprising: Coating module (1) according to claim 1, further comprising a conveyor system (3) for supporting and transporting the substrate (4) by a second surface of the substrate opposite the outer surface. 3. The coating module of claim 2, wherein the conveyor system includes support rollers. Coating module (1) according to claim 2 or 3, wherein the conveyor system comprises a temperature regulator configured to heat or cool a part of the substrate (4). Coating module according to any of the preceding claims, wherein the flexible film (5) further comprises openings (56), grooves or fibers. Coating module according to any one of the preceding claims, further comprising means (55, 57) for applying pressure to the distal part (54) of the flexible film (5). further comprising a retaining element (53) and a frame, said flexible film (5) being fixed to said retaining element (53), said retaining element (53) being mechanically connected to the frame by one or two side edges. The coating module according to any one of claims 1 to 6, wherein the coating module is 8. Coating module according to claim 7, wherein the retaining element is removable from the frame. further comprising a source of electromagnetic radiation disposed to irradiate the coating composition beneath the distal portion of the flexible film, and the flexible film is configured to absorb such electromagnetic radiation emitted by the source. Coating module according to any one of claims 1 to 8, which is transparent to. A coating system comprising a coating module according to any one of claims 1 to 9 and a substrate (4, 37), the coating device being arranged to coat the surface of the substrate. , the flexible film is arranged such that its distal part is in contact with the coated substrate (4, 37). Coating system (1) according to claim 10, wherein the substrate (4) is an endless ribbon;
a conveyor system comprising a set of rollers (3, 201, 204) for transporting said substrate (4) along a path;
a printing roller (203) for transporting the printing support (202) in contact with the outer surface of at least a portion of the substrate (4);
a printing head (101) arranged to thermally transfer a portion of the coating composition from the first surface of the substrate (4) to the printing support in contact with the substrate (4);
A thermal transfer printing device (200) comprising: 11. A system for producing endless ribbons, comprising a coating system according to claim 10, in which the substrate comprises a coating drum (37) comprising a cylinder and a coating drum (37) comprising a coating drum (37) comprising a cylinder; and means for rotating a coating drum. A method of coating a substrate (4), comprising:
providing a coating module according to any one of claims 1 to 9;
coating a first surface of the substrate with a coating composition to form a layer of coating composition (6) in the coating device;
transporting the substrate along a predetermined path such that a portion of the flexible film overlies the layer of coating composition before solidifying, drying, or fully curing;
A method of coating a substrate (4) comprising: the coating step comprises coating a first surface of the substrate in parallel with at least two layers of the coating composition, one separated from each other, the coating module comprising at least two flexible films, each of the 14. A method of coating a substrate (4) according to claim 13, wherein the flexible film is placed overlying one layer of the coating composition. A method of coating a substrate (4), comprising:
providing a coating module according to any one of claims 1 to 9;
coating a first surface of the substrate with a coating composition in the coating device to form a layer of coating composition (6) in the coating device;
transporting the coating device and the flexible film along a predetermined path such that a portion of the flexible film overlies the layer of coating composition before solidifying, drying, or fully curing; to do,
A method of coating a substrate (4) comprising:

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